<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>清除setTimeout定时器</title>
</head>
<body>
  <button>点击停止定时器</button>
  <script>
    var btn = document.querySelector('button')
    var timer = setTimeout(function () {
      console.log('爆炸了')
    }, 5000)
    btn.addEventListener('click', function () {
      clearTimeout(timer)
    })
  </script>
</body>
</html>